Extended Cold Preservation Times Are Not Associated with Increased Post-Transplant Mortality After Ex Vivo Lung Perfusion (EVLP) at a Dedicated Facility Using a Centralized Lung Evaluation System (CLES)

Abstract

<h3>Purpose</h3> Extended cold preservation times after EVLP have been associated with increased 1-year mortality. We evaluated the association of cold ischemic times before and after EVLP with 1-year post-transplant mortality in recipients of lungs perfused at a dedicated facility. <h3>Methods</h3> Data from a multi-center clinical trial (NCT02234128) were retrospectively analyzed (66 recipients). Cold ischemia time 1 (CIT1) was from donor cross-clamp/initial flush to EVLP start. CIT2 was from EVLP end to cold storage removal at transplant. Survival was compared for CIT groups using the log-rank test. Categorical variables were compared using the exact test for Pearson's Chi-square; continuous variables comparisons used the Mann-Whitney test. <h3>Results</h3> CIT1 ranged from 2.25 - 10 h. The top quartile (CIT1 > 5.68 h, n = 16) was classified extended. Donor demographics were similar in extended and non-extended groups. Recipient's age, gender, lung allocation score (LAS), and UNOS group were similar between groups. The extended group had fewer single lung grafts. The rates of 1-year mortality (6.25% extended vs 12% non-) were similar (p = 0.67). CIT2 ranged from 1.4 - 6.9 h. The top quartile (CIT2 > 4.25 h, n = 16) was classified extended. Extended group donors were younger with median age 26 [11 - 59] vs 37 [15 - 66] for non-extended (p = 0.01). Causes of death were more likely to be neurologic in the non-extended group (p = 0.03). Recipient's demographics were similar between groups. The rates of 1-year mortality (0% extended vs 14% non-) were not significantly different (p = 0.18). <h3>Conclusion</h3> In this clinical trial, extended CIT1 (> 5.68 h) and extended CIT 2 (> 4.25 h) were not associated with increased 1-year mortality in recipients of lungs perfused at a centralized EVLP facility. Although more data are needed, this supports that extended cold ischemic times are safe, which may allow longer timelines and increased use of donor lungs.